Atoms, Moles Etc

Question 1

What is an isotope?

Answer 1

Atoms of a single element (same atomic number) that differ in the number if neutrons in their nuclei (different masses)

Question 2

What is the mass number?

Answer 2

The combined number of protons and neutrons in a nucleus

Question 3

Different isotopes have the same chemical properties, explain why

Answer 3

Chemical properties depend on the number of outer electrons, so are the same in each isotope.

Question 4

Define the term relative atomic mass

Answer 4

The weighted mean mass of an atom of an element compared to 1/12 the mass of a C-12 isotope.

Question 5

What is the formula for hydrochloric acid?

Answer 5

HCl

Question 6

What is the formula for nitric acid?

Answer 6

HNO3

Question 7

What is the formula for sulfuric acid?

Answer 7

H2SO4

Question 8

What is the formula for ammonia?

Answer 8

NH4

Question 9

What is the formula for sodium hydroxide?

Answer 9

NaOH

Question 10

What is the formula for potassium hydroxide?

Answer 10

KOH

Question 11

What is an acid?

Answer 11

All acids contain the element hydrogen. When an acid is added to water, the acid releases hydrogen ions into the solution.

Question 12

What is a base?

Answer 12

A base is the opposite of an acid:

Bases accept the protons , bases neutralise acids.

Question 13

What donates protons?

Answer 13

An acid

Question 14

Give some examples of bases.

Answer 14

Metal oxides, metal hydroxides, ammonia, amines

Question 15

What is an alkali?

Answer 15

An alkali is a base that dissolves in water forming hydroxide ions. A soluble bass.

Question 16

What do alkalis release when added to water?

Answer 16

OH ions

Question 17

What is a salt?

Answer 17

A salt is a chemical compound produced when a H+ ion from an acid is replaced by a metal positive ion or an ammonium ion NH4+

Question 18

Acid + Alkali

Answer 18

Salt + water

Question 19

Acid + base

Answer 19

Salt + water

Question 20

What happens in a salt reaction?

Answer 20

The solid dissolves in the liquid

Question 21

What happens when an acid reacts with a carbonate?

Answer 21

Salt + water + carbon dioxide

Question 22

What happens when a metal reacts with an acid?

Answer 22

Salt + hydrogen

Question 23

What is the state symbol for salts?

Answer 23

Aq

Question 24

What is formed when acids are neutralised by aqueous ammonia?

Answer 24

Ammonium salt

Question 25

Whose model of the atom is the closest to accurate?

Answer 25

Bohr

Question 26

What are the four principles of the Bohr model?

Answer 26

1. Electrons can only exist in fixed orbits or shells and not anywhere in between 2. Each she'll has a fixed energy 3. When an electron moves between shells electromagnetic radiation is emitted or absorbed 4. Because the energy of shells is fixed, the radiation will have a fixed frequency.

Question 27

Define the term 'first ionisation energy'

Answer 27

The energy required to remove one electron from each atom in one mole if gaseous atoms to form 1 mole of gaseous 1+ ions

Question 28

Define 'ionic bond'

Answer 28

A chemical bond formed between two ions with opposite charges. Ionic bonds form when on atom gives up one or more electrons to another atom. These bonds can form between a pair of atoms or between molecules and are the type of bond found in salts.

Question 29

Define covalent bond

Answer 29

The bond formed by the sharing if a pair of electrons by two atoms.

Question 30

Define electronegativity.

Answer 30

The measure of ability of an atom or molecule to gain or lose an electron to form ions.

Question 31

What is the atomic number of an element?

Answer 31

The number of protons in a nucleus, the number of electrons in a neutral atom

Question 32

In group 1, why is less energy needed to ionise gaseous atoms of rubidium that gaseous atoms of sodium?

Answer 32

They have a larger atomic radius, more shells and more shielding so the electrons on the outside are further away from the nucleus and have less nuclear attraction.

Question 33

What is the shape of an s orbital?

Answer 33

Circle

Question 34

What is the shape of a p orbital?

Answer 34

Figure of 8

Question 35

How many electrons completely fill a p sub shell?

Answer 35

6

Question 36

How many electrons completely fill the third shell?

Answer 36

18

Question 37

How many electrons fill a d orbital?

Answer 37

2

Question 38

How many electrons can fill a d sub shell?

Answer 38

10